Got to remember that this was originally designed as a military weapon and as such was designed for combat. The flash suppressor does a very nice job of dampening the flash. Even with NVG's on at night and firing the weapon the flash was manageable, to the point, we could surpress the target area.
A friend of mime, bought a Bushy w/o a suppressor and he said the flash was quite distracting. He had a Ak style brake put on it in a very short amount of time.
If you are going to shoot at night, well worth the extra investment, if not, why worry.
As far as accuracy effects, someone else with more experience on that side, will have to pick up that thread. I have only shot the AR's/M16's with suppressors. Hope this helps!?